<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>表单属性选择器</title>
</head>
<body>
<body>
<input type="text" disabled><br>
<input type="text" ><br>
<input type="radio" name="gender" value="men" checked>男
<input type="radio" name="gender" value="women">女<br>
<input type="checkbox" name="hobby" value="study" checked>学习<br>
<input type="checkbox" name="hobby" value="sleep" checked>睡觉<br>
<select>
    <option>---请选择---</option>
    <option selected>本科</option>
    <option>专科</option>
</select>
</body>
<script src="js/jquery-3.3.1.min.js"></script>
<script>
    let in1=$("input:not(disabled)")
    alert("可用元素选择器"+in1.length)

    let in2 = $("input:disabled")
    alert("不可用选择器:"+in2.length)

    let in3=$("input:checked")
    alert("单选框被选中元素："+in3.length)

    let in4 =$("input:not(checked)")
    alert("单选框未被选中元素:"+in4.length)

    let in5 =$("select option:selected")
    alert("下拉框被选中元素:"+in5.html())






















</script>
</body>
</html>